Abstract: Abstract： Objective To establish a single nucleotide polymorphisms genotyping (SNP) method for a convenient, accu⁃ rate, and routine analysis of clinical samples. Methods Based on the design of oligonucleotide probe, the assay was per⁃ formed through three steps: the conjunction of the detection probe, universal amplification, labeling and ELISA reaction. The genotype of each SNP was revealed by reading signals of each set of reaction tubes. This assay was applied to detect sixtytwo plasma samples of lung cancer for circulating DNA for three SNPs of EGFR, c.2573T>G（L858R） , EGFR, c.2582T>A （L861Q） , EGFR, c.2155 G>T （G719C). Results were compared with those obtained by direct sequencing. Results The het⁃ erozygote mutation was identified for L858R by both methods, although no mutation was detected for L861Q and G719C. Six samples were identified as heterozygotes with the new method, and only two samples were unambiguously identified as het⁃ erozygotes by the direct sequencing. Two additional samples could not be identified as heterozygotes because the peak of mu⁃ tant allele was very low compared with that of wild allele. Conclusion The developed method enabled accurate identifica⁃ tion of SNP in a convenient manner, and which is adapted to routine analysis from heterogeneous samples unambiguously.

Key words: SNP, mutation, genotyping, ligase, ELISA